A digital signal is transmitted via various propagation paths in a wireless communication system. As the digital signal is transmitted and reproduced via various channels, various data errors caused by noise and signal deformation may be included in the digital signal. An error correction scheme is one of schemes for correcting such data errors. In the error correction scheme, an extra code is added to data to recover corrected data although the data has the error.
One of error correction schemes is turbo codes. As conventional turbo codes, duo-binary recursive systematical convolutional codes are used for a single input. Unlike the conventional turbo codes processed for only a single input at a time, non-binary turbo codes that process a plurality of inputs at the same time has been introduced.
Convolutional turbo codes (CTC), one of non-binary turbo codes, are channel codes used for “IEEE (Institute of Electrical and Electronics Engineers) Standard for Local and metropolitan area networks, Part 16: Air Interface for Fixed Broadband Wireless Access Systems” (referred to as “IEEE 802.16-2004”, hereinafter) standard approved in 2004. A CTC encoder has a structure in which duo-binary recursive systematic convolutional codes are connected via an internal interleaver. The performance of the CTC encoder relies on the characteristics of the internal interleaver.
When a transmitter encodes data by using the CTC encoder, padding bits irrelevant to the data is added to the data. The padding bits, required only for the CTC encoding process, are unnecessary in terms of data transmission efficiency, namely, dummy bits. Thus, as the padding bits increase, the data transmission efficiency of the system deteriorates. Therefore, an apparatus and method for transmitting data by removing the padding bits of the data are required.